Fox reality chief Mike Darnell exits

Mike Darnell, the president of alternative entertainment at Fox Broadcasting and one of the most influential programming executives of the last two decades, is resigning.

The diminutive Darnell, known for his wild curly locks and cowboy hat, is considered one of the godfathers of raunchy reality TV. He was the force behind shows such as "When Animals Attack" and "My Big Fat Obnoxious Fiance."

More recently, Darnell has been guiding "American Idol," Fox's musical talent program that at one point was the biggest TV show in America. Although based on a British hit called "Pop Idol" and brought to Fox's attention by Liz Murdoch, the daughter of Rupert Murdoch, whose News Corp. owns Fox, it was Darnell who played a key role in shaping the show for over a decade and keeping it on top of the ratings.

"I've been in reality since before it was even called that, and it has truly been an amazing ride," Darnell said in a statement. Although there has been gossip that Fox was looking to make a change, Darnell said the network had offered him a new long-term contract to stay but that he "decided it's time for a change."

Within the TV industry Darnell was often seen as a gutsy visionary who could take bizarre concepts and turn them into ratings hits. TV critics and purists, however, often saw much of the programming he created as a sign of cultural decay.

“Mike took risks at a critical time and was a pioneering force in shaping the reality programming genre that exists today," Rupert Murdoch said in a statement. "He’s a smart and fearless executive who will be missed."

Darnell's exit comes as "American Idol" finally appears to be running out of steam. The show is once again overhauling itself in the wake of disappointing ratings.

Darnell joined Fox in 1994 as a director of specials. Prior that he spent almost a decade as an executive at Fox's KTTV-TV Los Angeles.

A Fox spokesperson said the network is starting a search for a successor.